In the Session Initiation Protocol (referred to as SIP), a call can be transmitted to multiple locations, and no matter where the receiver is, the caller can always find the receiver. Such ability of the SIP makes it easy to realize multiparty call, one number service, call forwarding service and etc. in the Telecom network. SIP Forking can realize the function that the caller can always find the receiver wherever the receiver is. The SIP Forking represents that: a proxy server transmits a SIP request to multiple locations, and returns a response to the transmitter. In general, forking is classified as sequential forking and parallel forking, with the sequential forking representing that a proxy server contacts different receivers one by one, and the parallel forking representing that the proxy server simultaneously contacts different receivers. Compared with the sequential forking, the parallel forking can reduce the time for establishing a session. The SIP supports both the sequential forking and the parallel forking.
Next Generation Network (referred to as NGN) is the technology based on Internet Protocol (referred to as IP). Due to insecurity of the IP network, compared with the traditional Telecom network, the NGN is faced with security threats, wherein an authentication mechanism is used to identify the identity of a subject, which can avoid security threats such as counterfeit. In some cases, the receiver of a message may want to know the identity of the sender of the message, for example, the identities of spammers. Thus, the receiver of the message needs to authenticate the sender of the message.
However, in the Next Generation Network, with the situation of the SIP signaling forking, the authentication of some certain services (such as multiparty call, one number service, and call forwarding) in Telecom network can not be supported, nor can the sender's identity be identified. So far, no technical solutions for addressing the problems have been proposed.